1. Field of the Invention
The present invention relates to photosensitive compositions useful for the formation of fine resist patterns, and more particularly, to photosensitive composites of positive or negative-type which show a wide tolerance for alkaline development conditions when applied to lithographic technique or the like.
2. Description of the Prior Art
Photosensitive resins are being used widely in many fields of planar processes including the manufacture of semiconductors. However, the resist patterns are becoming increasingly fine in their structure in order to increase the density of the electronic devices, accompanying diversification in functions and sophistication of these devices. In addition, resistance to heat and resistance to reactive ion etching (RIE), which is being employed widely in recent times as a method of etching resist patterns, are required. As substances that can meet these requirements, there have been proposed in the past photosensitive composites that are formed by mixing photosensitive compounds with resins that consist of homopolymers or copolymers of vinylphenol group (reference: Japanese Patent No. 56-29261).
However, there was a problem that when use is made of such prior-art photosensitive compositions, resist patterns obtained by fixing after exposure have a very narrow tolerance to the development conditions in developing, although their resolving power is admittedly high. Namely, severe restrictions are imposed on the development temperature, the developer concentration, and others, and the pattern profile deteriorates rapidly if the temperature, concentration, and so on deviate from the respective predetermined values.
Because of this, in order to obtain fine resist patterns, it is necessary to hold the changes in the developer concentration at small values by setting the developer concentration at a low level, which was a considerable inconvenience in practice.